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| Titel |
A permanent array of magnetotelluric stations located at the South American subduction zone in Northern Chile. |
| VerfasserIn |
Dirk Brändlein, Oliver Ritter, Ute Weckmann, Kristina Tietze |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035197
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| Zusammenfassung |
| Monitoring the dynamic behavior of an active deep subduction system is focus of the
Integrated Plate Boundary Observatory Chile (IPOC), a permanent array of combined
geophysical and geodetic stations in Northern Chile which is operated since 2006 by
the GFZ German Research Centre for Geosciences. Magnetotelluric (MT) data is
gathered at seven out of a total of eleven observation sites. The MT set-up consists of
three component long period fluxgate magnetometers and Ag/AgCl electrodes to
measure the two horizontal components of the electric field. The signals of the
electromagnetic fields are continuously sampled at a rate of 20 Hz and at four sites
transferred via satellite link to the GFZ in Germany. The objective of the project
is to monitor and analyze electromagnetic data to decipher possible changes in
the subsurface resistivity distribution, e.g. as a consequence of large scale fluid
relocation.
We present vertical magnetic transfer functions as time series over a time span of more
than two years for the period range from 10-1 to 104 seconds. These vertical magnetic
transfer functions are sensitive to lateral changes of electric conductivity in the subsurface.
Miscellaneous components of these transfer functions show frequency dependent variations
with a periodicity of roughly one year. These effects can be observed at all sites of the array.
The causes are still unclear but we can rule out a direct meteoric influence on the
sensors because of the homogeneous climatic conditions of the desert in Northern
Chile. |
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